MOCLOBEMIDE EFFECTS ON PROLACTIN PLASMA-LEVELS IN HEALTHY-INDIVIDUALS- THE HORMONAL INCREASE INDUCED BY A SINGLE-DOSE IS MAINTAINED DURINGA 4-WEEK PERIOD OF DRUG INTAKE

Neuroendocrine challenge studies are frequently used to study the path ophysiology of psychiatric illnesses and the effects of psychotropic d rug treatment on brain monoamine function. Moclobemide, a reversible i nhibitor of monoamine oxidase, with predominant effects on the A-type of the enzyme, was administered to 15 healthy men. Seven out of the 15 also received single blind placebo a week before the moclobemide. The individuals received moclobemide as a single dose (150 mg), followed by doses of 150 mg three times a day, during a 4-week period. Plasma p rolactin was measured in the morning over a 150-min period, following the single dose, and then at the end of weeks 1, 2 and 4 of moclobemid e intake. The present data show an acute and transitory increase of pl asma prolactin levels after the single dose, and also during the long- term moclobemide administration. It might indicate that steady-state m oclobemide levels, during the long-term drug administration, were low and thus large fluctuations of drug levels occurred between doses. Thu s, it is suggested that larger doses or administering smaller doses mo re frequently, or both, may induce hyperprolactinaemia with clinical c onsequences.